As a crucial component of the HIV Treatment as Prevention approach, HIV testing has become a major tool in reducing HIV transmission. Persons who become aware of their HIV infection tend to reduce their sexual risk practices. Early identification facilitates more timely viral suppression, minimizing onward HIV transmission, including during the acute period when viral load tends to be high. While recent policies promote the routine offer of testing, additional strategies are needed to promote frequent testing for high-prevalence, high-incidence populations such as men who have sex with men (MSM). MSM are the largest risk group in the US and the only group in which new infections are increasing. MSM test more often than men who have sex with women. But relatively few MSM test as often as recommended by CDC - two to four times per year. More widespread frequent testing among MSM has ten potential to reduce the transmission of HIV in this population. While a small group of sexually active MSM have never tested for HIV, others test infrequently or delay testing until becoming symptomatic with AIDS. At the same time, a subgroup of MSM who test frequently have high levels of sexual risk; while unprotected sex can motivate HIV testing, testing confers a false sense of security and may lead to greater risk-taking. Research has identified individual and structural determinants for HIV testing in general; frequent HIV testing is, however, likely to respond to a different set of determinants. It is also ot known to what extent frequent testing is feasible and for which groups of sexually-active MSM. The few evaluated interventions that promote HIV testing in MSM have not addressed HIV testing that is frequent. In order to develop strategies that can promote frequent testing while reinforcing safer sex practices and avoiding risk compensation, an in-depth understanding is needed of the current HIV testing practices of MSM, how testing relates to sexual risk-taking, and the factors that promote or impede frequent HIV testing. In order to accomplish our goals, we propose a two-year developmental research project in which we will (1) conduct in-depth interviews with a purposive sample of 72 MSM in NYC, 18 to 39 years old, from diverse sociocultural backgrounds and with a range of HIV testing frequencies, and with 10 key informants; (2) use findings to identify potentially effective strategies to promote frequent testig for sexually- active MSM who never test, test infrequently, or test regularly but at less than optimal frequency, that simultaneously prevent frequent testing from becoming an alternative to safer sex practices; and (3) establish an NYC MSM HIV Testing Task Force of diverse stakeholders to assist in implementing the research, analyzing findings, and identifying prevention strategies. This project is a collaboration between the NYC Department of Health and Mental Hygiene and the HIV Center for Clinical and Behavioral Studies. Based on the study outcomes, we plan to develop, implement and evaluate a multi-component intervention to promote frequent HIV testing among diverse MSM in NYC.